Work supporting means for sewing machines



June 26, 1934; c. A. DEARBORN WORK SUPPORTING MEANS FOR SEWING MACHINES Fil ed Dec. 7, 1935 4 Shegts-Sheet 1 NVENTQR mum! (L. mm

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3 -c. A. DEARBORN WORK SUPPORTING MEANS FOR SEWING MACHINES Filed Dec. '7, 1933 4 Sheets-Sheet 2 WWHH:

INVENTOR June 26, 1934.

C. A. DEARBORN WORK SUPPORTINGMEANS FOR SEWING MACHINES Filed Dec. 7, 1933 4 Sheets-Sheet 3 June 26, 1934. c. A. DEARBORN WORK SUPPORTING MEANS FOR SEWING MACHINES Filed Dec. 7, 1933 4 Sheets-Sheet 4 INVENTOR M (L. m

2 QEYS Pat ented June 26, 1934 UNITED STATES WORK SUPPORTING MEANS FOR MACHINES SEWING Charles A. Dearborn, New York, N. Y., assignor to American Blind Stitch Machine Company, New York, N. Y., a. corporation of New.York

Application December 7, 1933, Serial No. 701,298 7 Claims. (01. 112-177) The present invention relates to improvements in overseaming blind stitch sewing machines of the power driven type illustrated for example in the machine of my Patent No. 1,025,082 granted April 30, 1912.

.The object of the present invention is to produce a simple and effective automatic work supporting mechanism for successively and uniformly varying the depth of work presented to the stitch forming mechanism, with a view to producing deep stitches passing through all of a series of layers of the work and intermediate shallow stitches which pass through only the folded over layers of the work, such, for instance,

as foundin a hem. r v

' The present improvements apply to the Dearborn type of blind stitch sewing machine in which a yieldingly mounted work support carries an intermittently oscillating ridge forming disk operated by suitable mechanism timed with reference to the'stitch forming and feeding mechanisms. In the normal operation of this mechanism the ridge forming disk has a forward movement imparted to it simultaneously with the feeding stroketo assist the feed by a fullin'g in action upon the base layer of the work and to present a ridge of the work 'in the path of the" needle. The adjustment of the work supporting member is such that in this normal operation the desired depth of material is uniformly presented in the path of the needle for each needle stroke.

In the present improvement the operating mechanism for the ridge forming member includes a floating pivot or journal for the bell crank lever through whichmotion is imparted to the ridge forming member. This floating pivot or journal is under the control of a cam mechanism that periodically shifts it to modify the active stroke of the ridge forming member, the

shift of the pivot or journal to one extreme position imparting a maximum movement to the ridge forming member while the shift-of the pivot or journal to its opposite position produces a minimum motion, the arrangement being such 5 that upon the maximum movement a rib of the greatest depth of material is presented in the path of the needle to efiect,a deep stitch, while in the minimum movement a reduced depth of material is presented and penetrated by the nee- 5 dle to make a shallow stitch. The shift of the controlling pivot or journal may be effected by any suitable cam operated through reduction gears of the required ratio, from the machine shaft. A manually operated throw-out cam is -51 provided to disengage the mechanism from its controlling cam when it is desired to operate the machine normally without the variations in. stitches.

In order that the invention may be fully understood it will first be described with reference to the accompanying drawings and the novelty afterwards pointed out in the annexed claims.

In said drawings Figure 1 is a side elevation of a blind stitch sewing machine embodying the present invention;

Figure 2 is a plan view of the same, parts being broken away for the sake of clearness;

Figure 3 is a vertical longitudinal sectional view taken on the line 33 of Figure 2;

Figure 4 is a view similar to Figure 3 showing the parts in a slightly changed position;

Figures 5 and 6 are detail vertical transverse sectional views taken respectively on the section lines 5-5 of Figure 3 and 66 of Figure 4;

Figure 7 is a detail perspective view of the automatic controlling mechanism for the ridge forming member;

Figure 8 is a view similar to Figure 1 showing parts in section with the automatic operating mechanism for the ridge forming and work supporting member thrown out'of action;

Figures 9, 10 and 11 are detail views illustrating different phases of the work performed by the improved machine.

The main frame of the machine of the type to which the present improvements are particularly applicable is formed of a single heavy casting having integral strengthening ribs and comprising essentially a rigid central base 1, the upwardly extending main arm 2 at the rear terminatingin the shaft bearing sleeve 3 from the left of which projects the forwardly extending arm 5 having horizontal bearings 4 for the needle rockshaft 15. This forward machine arm 5 also supports the looper and feed bar in the mannerhereinafter referred to. Extending forwardly and upwardly from the front of base 1 is the integral'arm 6 terminating in the sleeve '7 in which is secured the front horizontal bearing. shaft or rod 8 upon which is pivoted the work support 40, presently to be de-- scribed. v

10 is the main driving shaft of the machine journalled in the sleevebearing 3 of the rear arm 2 and having secured at one end the combined driving pulley l1 and flywheel 12. g The forwardly extending needle rock-shaft 15 journalled in bearings 4 has rigidly mounted upon its forward end the usual needle carrying the rod or shaft 8 carried in sleeve 7 in the upper.

rock-arm in which is mounted the usual curved needle 17. The machine is provided with the usual thread guides and tension devices which form no part of the present invention and are therefore not referred to in detail.

Secured to the rear end of the needle rockshaft 15 is a rock-arm 25 having universal joint connection with link 27 which encircles a spheroidal eccentric (not shown) mounted upon the main power, shaft 10 just inside crank disk 13. This needle operating mechanism .is the same as in my former patents.

40 is the worksupporting I the spaced bearing sleeves 41 which are freely journalled upon the oppositely projecting ends of end of frame arm 6. These'bearing sleeves 41 rest snugly against the finished vertical side faces,

of the sleeve 7 which they embrace. Projecting downwardly from one of the bearings 41 is an integral rock-arm 42 engaged at its lower end by a heavy coil spring 43 which extends rearwardly from said arm 42 to one arm. of a stout horizontal bell crank lever. 44 which is pivoted at 45 to the base 1. The other arm of hell crank 44 is engaged by an adjustable screw stop 46 threaded through a; rib 1a of the base frame, the

described arrangement giving to-the pivoted cloth supporting frame 40 a strong spring support to hold it in its normal horizontal working position, which is determined roughly by the adjustable screw stop 47 threaded through a bracket arm 6a. of front machine arm 6 and presented in the vertical plane of the rook-arm 42 by which it is engaged. See Figures 3,

The arm 42 of the work supporting frame 40 is engaged at a point above the screw stop 47 by a horizontal segmental plate 48 which is pivoted at 48c upon an integral lateral flange of the sewing machine arm 6. This segmental plate 48 is itself engaged by a frame; adjusting screw 49 which is threaded through an enlargement upon the inner rear surface of the machine arm 6 and extends the entire breadth of arm 6 and carries upon its outer end a milled head 49a having a crown wheel collar 50 on which is marked an index scale '51, (Figures 1 and 2). The crown wheel collar 56 operates in peripheral engagement with a small spring plunger 52 which is confined to slide in a-socket in the edge of the machine-arm 6 with its sented in latching engagement with the serrated inner edge of the collar 50, for the purpose ofretaining the tappet screw 58 in the desired adjusted position. I

The work supporting frame 40 is extended to the left to form a work supporting horn as is usual with this type of machine. Journalled in the work supporting frame 40 upon the usual conical axial bearing screws is the oscillating shaft 61 which carries the fulling in ridge forming rib or disk of the usual construction.

The usual independently yielding work supporting plates or platens 70 are mounted upon opposite sides of the ridge forming disk '60, each plate 70 being pivoted upon an arm or lever 72 pivoted at 73 uponframe 40 and provided with a spring 72a.

100 is the rigidly mounted presser foot projecting forwardly from the under face of machine arm 5 to a position above the ridge forming disk 60 and the work supporting platens 70. The presser foot is formed with the usual longitudinal slot into which a ridge of the work is pressed frame formed with.

4 and 8 of the drawingsf 'the shaft 10 alongside of the pulley 11.

conical outer end pre-,

by the disk so for the action of the stitch forming mechanism.

The looper mechanism of the machine is not involved in the present improvement and is not specifically shown, but it will be understood that the same form of looper is employed as has been used in the past in this type of machine, the looper being indicated at 76 carried on the forward end of the looper rod 77 carrying on its rear end a yoke pivoted upon a sleeve which is freely journalled upon the crank pin mounted.

in the angularly offset arm 80 of the crank disk 13. This looper and its operating mechanism will be clearly understood from my Patent No. 1,467,570 dated September 11, 1923'.

The feed mechanism may be of the general type shown in my Patent No. 814,026 dated March 6, 1906, the specific-structure of the same being immaterial to the present invention:

125 is the longitudinally movable rocking feed bar actuated at its rear end by the usual eccentric (not shown) upon main shaft 10.

The depression of the frame for placing the work upon the frame horn beneath the presser foot is accomplished by the usual foot treadle connected by a chain or wire 750. with a link 4011 hooked to the rear edge of frame 40.

I The shaft 61 has adjustably secured to it a downwardly. presented crank arm 62 to which is pivotally connected at 63, a link 64 in turn pivoted at 65 to one arm of a bell crank lever 67 pivotally mounted upon a screw bolt 68 which is mounted as will presently be described to constitute the floating pivot or journal for the variable operating mechanism of the ridge, formin rib.

The other arm of the bell crank lever67 is pivotally connected to the lower end of an eccentric link 69 having a yoke at its upper end which encircles the eccentric 14 secured upon The described mechanism for operating the ridge forming rib is the same as. heretofore used upon the Dearborn blind stitch sewing'machines with the important difference of the bell crank lever 67 being mounted upon a floating pivot or journal.

The floating pivot or journal bolt 68 is rigidly mounted in the forwardly projecting arm 130 extending from and rigidly secured to a rockshaft 131 which is freely journalled in a transverse bearing sleeve 132 formed in the frame arm 2 just above the frame base 1. The inner end of this rock-shaft 131 has secured to it a rock-arm 133 connected by a coil spring 134 with the base frame. A manually operated cam lock 135 is journalled upon the face of rock-arm 133 by-means of machine screw 136 in position to present the cam periphery of said lock in engagement with the upper face of the machine base 1 to move the rock-shaft 131 and connected parts into inoperative position and lock them against action in that position, as shown in Figure 8 of the drawings.

The outer end of the rock-shaft 131 carries an upwardly extending rock-arm 137 having at its upper end an anti-friction roller 138 which operates in peripheral engagement with the controlling cam 139 mounted upon and rotating 142 may have any desired ratio such as 2: 1, 3:1, etc., depending upon the number of impulses it is desired to impart to the rock-shaft which carries the floating pivot or journal and controls the variations in stitches.

When the cam lock 135 is shifted rearwardly upon its pivot to throw its locking cam in engagement with the machine frame base, as shown in Figure 8 of the drawings, the rock-arm 137 carrying pivot or journal 68 will be shifted forwardly, the anti-friction roller 138 being held thereby out of the path of the high portion of controlling cam 139, so that the improved controlling mechanism will be held out of operation and the machine will be operable in its normal manner to produce a succession of stitches of uniform depth, the depth for all of the stitches depending upon the adjustmentof the work supporting member 40 with reference to the fixed presser foot.

When it is desired to produce a piece of work with a succession of deep stitches with intervening shallow stitches, the cam lock 135 is shifted to its forward position which permits the spring 134 to rock the shaft 131 forwardly and move the anti-friction roller 138 of rock-arm 137 into peripheral engagement with the controlling cam 139. In this active position of the improved controlling mechanism the high part of the controlling cam 139 intermittently rocks the shaft 131 to slightly raise floating pivot or journal 68 with the result that the ridge forming member will be rocked to its extreme position for presenting the greatest thickness of work in the path of the needle, under the selected adjustment of the work supporting frame. This extreme movement oc curs every time the high part of the controlling cam 139 actuates the floating pivot or journal 68, and the number of times such movement is produced for a given period of stitches will depend upon the gear ratio between the shaft and the controlling cam. When the floating pivot or journal 68 is in its lower position by reason of the passage of the low portion of the controlling cam 139, the ridge forming member is moved to a less degree so that a relatively smaller depth of work is presented in the path of the needle. The position of the parts shown in Figures 4 and 6 illustrates the formation of the deep stitch, the ridge of work resting upon the high part of the ridge forming member 60. The position of these parts shown in Figures 3 and 5 indicates the formation of a shallow stitch, the high part of the ridge forming member 60 being presented just short of the path of the needle so that the needle penetrates only the folded over layers of the work.

Figure 9 shows the underside of a piece of work in which the hem is joined to the base material. Figure 10 shows the right side of the same piece of work from which it will be observed that the deep stitches indicated at a are widely spaced. The intermediate stitches indicated at b in Figure 9 are shallow stitches which pass through the folded over layers of the material and do not penetrate the base layer. In Figure 11 the difference in depth of the stitches a and b is clearly shown. These stitches b are sometimes called skip stitches because they pass through and bind the folded over layers and .do not enter the base layers of the material.

It will be observed that the work supporting frame 40 projects rearwardly from the machine arm 6 which is just the reverse of the arrangement of the work supporting frame that has heretofore been employed in this type of machine.

J By the eccentric link connection between the power shaft and the shaft 61 of the ridge forming disk it will be observed that the forward stroke of the disk is effected by-an upward thrust upon the rock-arm 62. This upward thrust in actively moving the ridge forming disk is exerted in the same direction as the spring induced upward pressure of the work supporting frame which is important in that it cooperates with and does not conflict with the normal spring support of the work supporting frame.

I claim:

1. The combination, in a sewing machine, with a driving shaft, a yielding work support, a ridge forming member movably mounted on said work support, and operating means between said shaft and said ridge forming member, of automatic controlling means for varying the action of said operating means, and manually operated means .mechanism, and a spring sustained work support movably mounted upon said frame in operative relation with said presser foot, with a ridge forming member movably mounted upon said work support in position to press a rib of work against said presser foot, operating means for actuating said ridge forming member, automatic controlling means for varying the action of said operating means, and manually operated means for throwing out said controlling means.

3. In a sewing machine, the combination with a machine frame, a presser foot upon said frame, a driving shaft, suitable stitch forming mechanism, and a spring sustained work support movably mounted upon said frame in operative relation with said presser foot, of an oscillatory shaft mounted on said work support, a ridge forming member carried by said oscillatory shaft in position to press a rib-of work against said presser foot, a rock-arm operatively connected with said oscillatory shaft, means operating said rock-arm from said driving shaft, a floating pivot or jourtion with said presser foot, of an oscillatory shaft mounted on said work support, a ridge forming member'carried by said oscillatory shaft in position to press a rib of work against said presser foot, a rock-arm operatively connected with said oscillatory shaft, means operating said rockarm from said driving shaft, a floating pivot or journal upon which said rock-arm is mounted, a rocking member supporting said floating pivot or journal, and means operated by said driving shaft for operating said rocking member and automatically shifting said floating pivot or journal to vary the stitching.

5. In asewing machine, the combination of a.

machine frame, a presser foot mounted upon said frame, a driving shaft journalled in said frame, suitable stitch forming mechanism, and a spring sustained work support pivotally mounted upon said frame in operative relation with said presser foot, with an oscillatory shaft journalled upon said work support, a ridge forming member mounted upon said oscillatory shaft in position to press a rib of work against said presser foot, a rock-arm driven by said driving shaft and operatively connected with said oscillatory shaft, and a rocking member carrying a floating pivot upon which said rock-arm is journalled, and operating means between said driving shaft and said rocking member.

6. In a sewing machine, the combination with a machine frame, a presser foot upon said frame, a driving shaft, suitable stitch forming mechanism, and a spring sustained work support movably mounted upon said frame in operative relation with said presser foot, of an oscillatory shaft mounted onsaid work support, a ridge forming member carried by said oscillatory shaft in position to press a rib of work against. said presser foot, a rock-arm operatively connected with said oscillatory shaft, means operating said rockearm from said driving shaft, a floating pivot or journal upon which said rock-arm is mounted, a rocking member adjustably supporting said floating pivot or journal, means operated by said driving shaft for operating said rocking member, for automatically shifting said floating pivot or journal to vary the stitching, and a manually shiftable cam lock pivoted upon said rocking member and adaptedv to be moved into engagement with the machine frame for holding said rocking member inactive.

'Leln a sewing machine, the combination with a machine frame, a presser foot upon said frame, a driving shaft, suitable stitch forming mechanism, and a spring sustained work support mov ably mounted upon said frame inoperative relation with said presser foot, of an oscillatory shaft mounted on said work support, a ridge forming member carried by said oscillatory shaft in position to press a rib of work against said presser foot, a rock-arm operatively connected with said oscillatory shaft, means operating said rock-arm from said driving shaft, 2. floating pivot or journal upon which said rock-arm is mounted, a rocking member supporting said floating pivot or journal, and means operated by said driving shaft for operating said rocking member, said means including an arm projecting from said rocking member, a cam acting upon said arm, and reduc'-' mg gears between said driving shaft and said cam.

CHARLES A. DEARBORN. 

